Electrical device



Nov. 20, 1934. E, s TRUE 1,981,681

ELECTRICAL DEVICE Original FiledV Dec. 23, 1927 UNITED STATES PATENTOFFICE ELECTRICAL DEVICE Edwin S. True, Oak Park, Ill.

Application December 23, 1927, Serial No. 242,130 Renewed June 7, 193321 Claims. (Cl. 200-95) My invention relates to electrical devices andmember 16 also of insulating material, and a has particular relation toelectromagnetically tubular member 17 of non-magnetizable material,operated electric switches. such as brass, for maintaining the endportions The principal object of my invention is to proand the tubularportion 16 in proper relative vide an electromagnetically operatedelectric position. The coil 14 is maintained in position 60. switch thatshall be extremely sensitive in its within the casing l1 by means of atubular sleeve operation and at the same time capable of con- 18 ofnon-magnetizable material that is securely trolling circuits that are tobe traversed by curfitted within suitable apertures in the upper andrents of relatively high values. lower portions of the casing 11. Whenthe de- 10 It is a further object of my invention to provice isassembled the sleeve 18 extends through 65 vide a switch of theabove-identied character the tubular member 17 of the spool upon whichembodying independent means for making nuthe coil 14 is wound and thusmaintains the coil merous desired adjustments. in fixed position withinthe casing 11.

Further objects and advantages of my inven- A core unit for the coil 14is assembled within tion will appear from a consideration of the folanon-magnetizable tubular casing 19 that is 70 lowing detaileddescription in connection with adapted to be disposed within the sleeve18 when the accompanying drawing, in which: the device is assembled. Atubular stationary Figure 1 is a top plan view of a switch embodycoremember 20'is securely xed within the upper ing my invention; part of thecasing 19 and is provided with an 20 Fig. 2 is a. front elevational viewof the switch upwardly extending screw-threaded portion that 75 shown inFig. 1; is adapted to be engaged by a correspondingly Fig. 3 is avertical sectional view taken along screw-threaded adjusting nut 21. Thevertical the line III- III of Fig. 2; position of the core assembly unitmay be ad- Fig. 4 is a fragmentary side elevational view justed withrespect to the casing 11 by adjusting showing the contact members of theswitch emthe nut 21 as desired. A set-screw 22 is pro- 80 bodying myinvention in cooperative engagement; vided to secure the nut 21 in fixedposition with and respect to the core member 20 when the desired Fig. 5is an enlarged fragmentaryV sectional adjustment has been made. viewshowing the method of mounting the mov- A movable core member 23 ofmagnetizable maable contact member in the switch embodying terial isdisposed Within the lower portion of the g5 my invention. casing 19 andis secured to the lower extremity Referring to the drawing, a switchembodying of a switch-actuating member 24 of non-magmy invention,designated in general by the refnetizable material. The actuating member24 is erence character 10, comprises a casing or suppreferably ofhexagonal cross-section and exporting frame 11 of magnetizable materialthat tends upwardly from the movable core member 23 90' is provided withstuds 12 for securing the switch through an auxiliary tubular coremember 25 to a mounting panel 13. The casing 11 is of subthat is held inplace within the stationary core stantially semicylindrical form at thefront member 20 by an annular member 26 of nonthereof and the sides ofthe casing extend backmagnetizable material that is fixed within the 4owardly from the semicylindrical portion in sublower extremity of theopening through the core 95 stantially perpendicular relation to thepanel 13. member 20. The opening through the auxiliary The casing 11-isopen on the side adjacent the core member 25 is preferably of circularcrosspanel 13 to permit the insertion of a solenoid coil section,whereby a bearing is provided for the v 14 therein when the device isbeing assembled actuating member 24 in which it is possible for previousto being mounted on the panel 13. The the members 24 and 25 to engageeach other 100 side walls of the casing 11 are terminated a short alongno more than two lines of contact. The d distance in front of the panel13 to leave a space bearing friction between the members 24 and 25 14aat each side of the casing to facilitate venis thus reduced to aminimum, particularly betilation of the interior of the casingV thusprecause no opportunity is afforded for particles of i0 venting the coil14 from attaining a dangerous dirt or the like to become lodged betweensaid 105 temperature when it is energized for extended members. periods.The upper extremity of the auxiliary core mem- The coil 14 is wound upona spool comprising ber 25 comprises a reduced diameter portion 25aannular end portions 15 of insulating material, about which the lowerextremity of a coiled such as fiber or the like, a longitudinal tubularnon-magnetizable compression spring 27 is dls- 110 posed. The outsidediameter of the spring 25 is only slightly less than the inside diameterof the core member 20, so that the spring 27 is maintained in properposition within the said core member. The upper extremity of the spring27 is disposed around a reduced diameter portion 28a of anon-magnetizable annular member 28 that is screw-threadedly engaged bythe actuating member 24 near the upper extremity thereof. The uppersurface of the main portion of the annular member 28 comprises anotherreduced diameter portion 28h upon which a centrally apertured contactmember 29 of disc form is supported. The contact member 29 is of copperor other suitable current-conducting material.

The centrally disposed aperture in the disc 29 is of slightly greaterdiameter than that of a third reduced diameter portion 28e of theannular member 28, but is of smaller diameter than that of the reduceddiameter portion 28h. The thickness of the reduced diameter portion 28Cis somewhat greater than that of the disc 29. A lock-nut 30 is adaptedto engage the screwthreaded portion of the actuating member 24 and theupper surface of the reduced diameter portion 28e of the annular member28 to lock the said annular member in any desired position on theactuating member 24. By reason of the construction of the annular member28, which is more clearly shown in the-detailed view of Fig. 5,

it will be seen that this member provides a loose mounting for thecontact member 29 with respect to the actuating member 24.

A closure member 31 is secured within the lower extremity of the casing19 by means of laterally disposed pins 32. A centrally disposedscrewthreaded opening through the closure member 31 is adapted toreceive an adjusting screw 33 which may be locked in any desiredposition with respect to the member 31 by means of a lock-nut 34. 'I'hehead of the screw 33 and the lock-nut 34 are provided with knurledportions to facilitate manual adjustment and setting of these members.The upper extremity of the screw 33 extends into the casing 19 toprovide an adjustable stop for determining the lowermost position of themovable core member 23.

Two laminated stationary contact members 3.5 are mounted on brackets 36which are secured to the panel 13 by means of screws 37 and terminalstuds 38. 'I'he brackets 36 are provided with parallel side wallsextending outwardly from the panel 13 and are adapted to receivetransversely disposed clamping bolts 39. The bolts 39 also extendthrough suitable apertures in rocker members 40 of substantiallysemicylindrical. form disposed in relatively close-rlttting relationbetween the side walls of each of the brackets 36. The contact members35 are secured to the flat surfaces of the rocker members 40 by bolts orcap-screws 41 and extend at an inclined angle toward the contact disc29. The laminations of the contact members 35 are Vof decreasing length,proceeding inwardly from the outer laminations, whereby the lowerextremities of the contact members 35 present slightly inclined surfacestoward the at upper surface of the contact disc 29.

The contact members 35 are so `disposed that when the contact disc 29 isactuated upwardly into engagement therewith the outer laminations of thestationary Contact members will be engaged first and the interiorlaminations will be engaged subsequently by the disc 29. When the disc29 is actuated to its extreme upper position all of the laminations ofthe stationary Contact members 35 are engaged thereby. Theselaminations, being of resilient material, are separated one from anotheras illustrated in the detailed view of Fig. 4, when the disc 29 is fullyactuated into engagement therewith.

The switch embodying my invention is particularly adapted to be utilizedin electrical systems requiring extreme sensitivity of operationcombined with relatively large current carrying capacities. An exampleof a system requiring the provision of such a switch is an electrolysisprotective system, in which the main contact members of the switch areconnected between a structure to be protected from corrosion and asuitableground conductor or vthe like. In such systems itis essentialthat the switch be closed when a very slight potential of predeterminedpolarity exists between the structure to be protectedand the earth. Whenthe switch is closed in response to the occurrence of this condition,which may be eiected in response to the operation bf a delicatepolarized relay or other suitable device, it is necessary that theswitch provide a path of very low resistance to permit relatively heavycurrents to traverse the same. Therefore, it will be seen that it isessential that the switch must be extremely sensitive in its operationas well as being so constructed as to be capable of conducting currentsof large values.

These objects are obtained in the switch embodying my invention byreason of the resilient mounting for the movable contact member providedby the spring 27. The resiliency of this spring may be varied as desiredby adjusting the position of the annular member 28 on the actuatingmember 24. When the desired adjustment is obtained the position of theannular member 28 on the actuable member 24 is fixed by tightening thelock-nut 30. Previous to making this adjustment the lowermost positionof the movable core member 23 with relation to core members 20 and 35will have been determined by adjusting the screw 33 and locking the samein position by the lock-nut 34.-.

The magnetic air-gap between the movable core member 23 and thestationary core member 20 is thus determined, which controls the degreeof energization of the 'coil 14 that is required to actuate the coremember 23 for any given adjustment of the spring 27.. It is preferableto adjust the spring 27 so that the core member 23 is barely lifted fromthe stop-screw 33 when the coil 14 is de-energized. The entire weight ofthe moving part is thus supported by the spring 27 and the only forcerequired to actuate the movable members is that required to,I overcomethe inertia thereof plus the slight additional force required to liftthese parts as the spring 27 is extended. The lifting force, however, isvery slight, since the distance that the moving parts must be lifted tocause the contact disc 29 to engage the stationary contact members 35 isvery slight as compared with the length of the spring 27.

The length of the electrical air-gap between the contact disc 29 and thestationary contact members 35 when the moving parts of the switch are intheir lowermost positions, that is, when the coil 14 is cle-energized,may be varied by adjusting the position of the adjusting-nut 21 on thescrew-threaded upper extension of the to the coil 14 and the casing 11without affecting the adjustments of the spring 27 or the stopscrew 33in any way. When the desired adjustment of the electrical air-gap isobtained, the adjusting-nut 21 may be fixed in position with respect tothe core member 20 by tightening the set-screw 22.

Still another adjustment that may be made independently of all of theadjustments previously described is that of the angle of incline of thestationary contact members 35. This angle, which .is commonly designatedas the pitch of the laminated contact members, may be adjusted byloosening the clamping bolts 39 and turning the contact members 35 andthe rocker members 40 thereabout. When the desired pitch is obtained the`contact members 35 are securely locked in position by tightening theclamping bolts 39. It is preferable that this adjustment be so made thatthe longest or upper lamlnations of the contact members 35 will beengaged by the contact disc 29 before any of the other 1aminations areso engaged.

The electrical system with which the switch is associated may be soarranged that a circuit of relatively low current-carrying capacity iscompleted in response to the operation of a very delicate and sensitivecontrol relay, as previously described. The contact members 35 may be soconnected in relation to the electrical system that initial engagementbetween said contact members and the contact disc 29 will complete acircuit shunting the contact members of the control relay to permit acurrent of a much larger'value to traverse the coil 14. The energizationof this coil may thus be increased to cause a greater lifting force tobe applied to the core member 23, which, in turn, applies a strongeroperating pressure to the contact disc 29. This disc is thereuponactuated more firmly into engagement with the stationary 'contactmembers 35 to cause successive laminations thereof to be engaged by thecontact disc. As increasing pressure is applied to the disc 29 and morelaminations of the contact members 35 are successively engaged thereby,the current-carrying capacity of the switch is further increased, withthe result that the-energization of the 'coil 14 is likewise increasedto actuate the contact disc to its uppermost position, in which all ofthe laminations of the stationary contact members 35 are firmly engagedby the disc 29. Thus, it will be seen that while the switch embodying myinvention is extremely sensitive in its initial operation, it may bearranged to complete a circuit connection of large current-carryingcapacity.

When current ceases to traverse the energizing circuit of the coil 14,the movable core memco ber 23 is permitted to return to its originalposition, as shown in Fig. 3 of the drawing. The downward movement ofthe moving parts is lim- \ited by the adjusting screw 33 to prevent theoccurrence of any rebound of the moving parts. 65 The adjusting screw 33also insures that the spring 27 will never be compreed to a greaterdegree than that corresponding to the normal deenergized condition ofthe switch. The calibration of the spring 2'?, therefore, remainsconstant,

70 thereby preventing any change from occurring in the degree ofenergization of the coil that is required to effect initial operation ofthe switch.

By making all of the proper adjustments as hereinbefore described, it ispossible to determine very 75 accurately the degree of energization ofthe coil 14 that is required to operate the switch and it is essentialthat this value remain constant until one or more of these adjustmentsare changed.

The bushing member 26 of non-magnetizable material is effective toprevent chattering or sticking of the core member 25. It is thus insuredthat when the coil 14 is energized the contact disc 29 will bemaintained securely in engagement with the contact members 35 and thatwhen the coil 14 is cle-energized such engagement will be immediatelybroken. The relatively loose mounting of the disc 29 with respect to theoperating member 24 permits the disc 29 to engage the contact members 35in the position which y establishes the greatest possible area ofcontact surface. If the contact members 35 were not perfectly adjustedor if there were any slight irregularities in the contact surfaces ofthese members, the contact disc 29 would not make perfect contacttherewith unless this method of mounting were utilized.

From the foregoing description it will be seen that I have provided anelectromagnetically operable switch of extreme sensitivity and of greatcurrent carrying capacity. This switch embodies means for makingnumerous essential adjustments and each of these means is entirelyindependent of all of the other of said means. A switch constructed inthis manner is capable of accomplishing all of the functions required ofsuch a switch in the best possible manner and is capable of adjustmentover such a broad range as to render the switch adaptable to systems ofwidely varying requirements.

While I have shown only one specific embodiment of my invention, it willbe understood that various changes and modifications may be made in thedetails of construction without departing from the spirit and scope ofmy invention, as set forth in the appended claims.

I claim as my invention:

1. A solenoid device comprising a magnet coil, a core thereforcomprising a stationary portion and a movable portion, said portionsbeing adapted to be separated by an air gap when said magnet coil istie-energized, parts associated with and supported by said movableportion, resilient means for suspending said movable portion in avertical balanced position within said magnet col and opposing only theaction of gravity on said movable portion and associated parts when saidmagnet coil is de-energized, and an adjustable member for varying thelength of the air gap between the portions of the core when the magnetcoil is de-energized and for limiting the movement of said movableportion.

' 2. A solenoid device comprising a magnet coil, a core thereforcomprising a stationary portion and a movable portion, said portionsbeing adapted to be separated by an air gap when said magnet coil isfie-energized, adjustable resilient means for suspending said movableportion within said .magnet coil, and an adjustable member for varyingthe length of the air gap between the portions of the core when themagnet coil is de-energized and an adjustable member for limiting themovement of said movable portion.

3. A solenoid device comprising a magnet col, a. core thereforcomprising a stationary portion and a movable portion, said portionsbeing adapt- 345 ed to be separated by an air gap when said magnet coilis de-energized, an adjustable stop member for limiting the length ofsaid air gap, resilient means for supporting said movableportion of thecore and means for varying the effec- 153 tiveness of said resilientmeans independently of said adjustable stop member.

4. A solenoid device comprising a magnet coil, a supporting frame ofmagnetizable material therefor, a vertical sleeve of non-magnetizable'material extending through said magnet coil and supported by saidframe, a sleeve core member of magnetizable material fixed within theupper portion of said vertical sleeve, a movable core membervofmagnetizable material disposed within said vertical sleeve beneath saidsleeve core member and resilient means for supporting said movable coremember when said magnet coil is deenergized.

5. A solenoid device comprising a magnet coil, a supporting frame ofmagnetizable material therefor, a vertical sleeve of non-magnetizablematerial extending through said magnet coil and supported by said frame,a sleeve core member of magnetizable material fixed within the upperportion of said vertical sleeve, a movable core member of magnetizablematerial disposed Within said vertical sleeve beneath said sleeve coremember and adjustable resilient means for supporting said movable coremember when said magnet coil isl de-energized.

f 6. A solenoid device comprising a magnet coil, a supporting frame ofmagnetizable material therefor, a vertical sleeve of non-magnetizablematerial extending through said magnet coil and supported by said frame,a sleeve core member of magnetizable material fixed Within the upperportion of said vertical sleeve, a movable core member ofmagnetizablematerial disposed Within said vertical sleeve beneath saidsleeve core member, a non-magnetic rod secured to said movable coremember and extending upwardly through said sleeve core member, anelectrical contact member supported by said rod near the upper'extremity thereof and a compression spring for resiliently supportingsaid movable core member, rod and electrical contact member with respectto said sleeve core member when said magnet coil is de-energized.

7. A solenoid device comprising a magnet coil, a supporting frame ofmagnetizable material therefor, a vertical sleeve of non-magnetizablematerial extending through said magnet coil and supported by said frame,a sleeve core member of magnetizable material fixed within the upperportion of said vertical sleeve, a movable core member of magnetizablematerial disposed within said vertical sleeve beneath said sleeve coremember, a rod of polygonal cross-section secured to said movable coremember and extending upwardly through said sleeve core member, anelectrical contact member supported by said rod near the upper extremitythereof and a compression spring co-acting between said sleeve coremember and said contact member to constitute a resilient support forsaid movable core member, rod and contact member when said magnet coilis deenergized.

8. A n electrical device comprising an electromagnet, co-operatingspaced stationary and movable core members therefor, a contact memberactuable by said movable core member, resilient means for' supportingsaid movable core member and said actuable contact member, a stationarycontact member adapted to be engaged by said actuable contact memberwhen said electromagnet is energized, and independent means foradjusting the magnetic air-gap between said spaced core members, foradjusting said resilient supporting means and for adjusting the positionof said actuable contact member with respect to said stationary contactmember when said electromagnet is de-energized.

9. An electrical device comprising an electromagnet, co-operating spacedstationary and movable core members therefor, a contact member actuableby said movable core member, resilient means for supporting said movablecore member and said actuable contact member, an inclined laminatedstationary contact member adapted to be engaged by said actuable contactmember when said electromagnet is energized, and independent means foradjusting the magnetic air-gap between' said spaced core members, foradjusting said resilient supporting means, for adjusting the position ofsaid actuable contact member with respect to said laminated sta-'-tionary contact member whensaid electromagnet is de-energized, and foradjusting the angle of incline of said laminated stationary contactmember with respect to said actuable contact member.

10. An electrical device comprising an electromagnet, co-operatingspaced stationary and movable core members therefor, a contact memberactuable by said movable core member, resilient means for supportingsaid movable core member and said actuable contact member, an inclinedlaminated stationary contact member adapted to be engaged by saidactuable contact member when said electromagnet is energized, andindependent means for adjusting said resilient supporting means and forvadjusting the angle of incline of said laminated stationary contactmember with respect to said actuable contact member.

11. An electrical device comprising an electromagnet, co-operatingspaced stationary and movable core members therefor, a contact memberactuable by said movable core member, resilient means for supportingsaid movable core member and said actuable contact member, an inclinedlaminated stationary contact member adapted to be engaged by saidactuable contact member when said electromagnet is energized, andindependent means for adjusting the magnetic airgap between said spacedcore members, for adjusting said resilient supporting means, and foradjusting the angle of incline of said laminated stationary contactmember with respect to said actuable contact member.

12. An electrical device comprising an electromagnet, co-operatingspaced stationary and movable core members therefor, a contact. memberactuable by said movable core member, resilient means for supportingsaid movable core mem' ber and said actuable contact member, an inclined13. An electrical device comprising an electromagnet, co-operatingspaced stationary and movable core members therefor, a contact memberactuable by said movable core member, resilient means for supportingsaid movable core member and said actuable contact member, an inclinedlaminated stationary contact member adapted to be engaged by saidactuable contact member when said electromagnet is energized, andindependent means for adjusting said resilient supporting means, foradjusting the position of said actuable contact member with respect tosaid laminated stationary contact member when said electromagnet isde-energized, and for adjusting the angle of incline of said laminatedstationary contact member` with respect to said actuable contact member.

14. An electrical device comprising two cooperating contact members, oneof said contact members being composed of exible laminations arranged toprovide a contact surface inclined With respect to the contact surfaceof the other of said contact members when said members are not inengagement, and means for adjusting the angle of such incline comprisinga rocker member, means for securing the laminated contact member to saidrocker member, a bracket member for supporting said rocker member, andmeans for clamping said rocker member in any desired xed position withrespect to said bracket member.

15. An electrical device comprising a plurality of stationary contactmembers, a movable contact member adapted to engage said stationarycontact members, a member for actuating said movable contact membersubstantially perpendicularly with respect to the contact face thereof,and means for tiltably mounting said movable contact member on saidactuating member whereby said movable contact member may assume aposition conforming to the positions of said stationary contact memberswhen actuated into engagement therewith, said stationary contact membersbeing of laminated formation with the laminations thereof set at anangle with respect to the contact face of said movable contact memberwhereby said laminations may be flexed upon engagement thereof by saidmovable contact member while the tilting of the latter insures themaking of contact with all of said laminations.

16. An electrical device comprising a plurality of stationary contactmembers, a movable centrally apertured contact disc adapted to effectelectrical circuit connection therebetween, a screw-threaded rod foractuating said contact disc and means for supporting said contact discon said rod comprising an internally screwthreaded annular memberco-operating with said rod and having a reduced diameter cylindricalportion of greater thickness than the contact disc and substantiallyless in diameter than the centrally located aperture in said disc, and alocknut of greater diameter than said aperture for cooperating with saidrod and said annular member to maintain said disc in tiltably supportedrelation to said rod.

17. An electrical device comprising an electromagnet, a supporting frameof magnetizable material therefor, a tubular casing of non-magnetizablematerial extending through said electromagnet and supporting frame, astationary core member of magnetizable material secured within saidcasing, a movable core member of magnetizable material disposed withinsaid casing in spaced relation to said stationary core member, anactuating member secured to said movable core member, an actuablecontact member adjustably mounted on said actuating member, aco-operating stationary contact member, resilient means co-actingbetween the stationary core member and the actuable contact member andcontrolled by the adjustment of the actuable contact member, andindependent means for adjusting the position of said casing within saidelectromagnet and supporting frame to vary the position of said actuablecontact member with respect to said stationary contact member when saidelectromagnet is de-energized.

18. A device of the character described, comprising a magnet coil, amagnetizable core therefor including a tubular stationary portionextending into one end of said coil and a movable portion extending intothe other end of said coil, with a magnetic air gap between saidportions, a stationary contact member, a cooperating movable contactmember actuable by said movable core portion, a member secured tosaidmovable core portion, extending through said tubular core portion andcarrying said movable contact member therebeyond, and means forindependently adjusting the lengths of the magnetic air gap and theContact air gap whereby variations in the operating pressure between thecontact members may be effected.

19. A device of the character described, comprising a magnet coilarranged on a vertical axis, a magnetizable core therefor including atubular stationary portion extending within the upper portion of saidcoil and a movable portion extending within the lower portion of saidcoil, with a magnetic air gap between said portions, a stationarycontact member, a cooperating movable contact member actuable by saidmovable core portion, a member secured to said movable core portion,extending upwardly therefrom through said tubular core portion, andcarrying said movable contact member thereabove, and means forindependently adjusting the lengths of the magnetic air gap and thecontact air gap whereby variations in the operating pressure between thecontact members may be effected.

20. A device of the character described, comprising a magnet coilarranged on a vertical axis, a magnetizable core therefor including atubular stationary portion extending within the upper portion of saidcoil and a movable portion extending within the lower portion of saidcoil, a movable contact member actuable by said movable core portion, amember secured to said movable core portion, extending upwardlytherefrom through said tubular core portion and carrying said movablecontact member thereabove, resilient means opposing the action ofgravity on said movable core portion, and means for adjusting thepressure of said resilient means to vary the degree of energization ofsaid magnet coil which is required to actuate said movable core portion.

21. A device of the character described, comprising a magnet coiladapted to be variably energized, a magnetizable core therefor includinga tubular stationary portion extending into one end of said coil and amovable portion extending into the other end of said coil, a movablecontact member actuable by said movable core portion, a member securedto said movable core portion and extending through said tubular coreportion and carrying said movable contact member therebeyond, resilientmeans for holding said movable core portion in predetermined positionwith respect to said xed core portion, and means ior adjusting theposition of said movable core portion when said magnet coil isde-energized.

EDWIN S. TRUE.

